1. Field of the Invention
The present invention is directed to electrical equipment and more particularly to an electrical transformer having a core produced from folded strips of amorphous metal material.
2. Background
The use of amorphous metal strips in electrical transformer cores is well known. For example, U.S. Pat. No. 4,734,975 to Donald E. Ballard and Willi Klappert assigned to General Electric Company discloses a Method of Manufacturing an Amorphous Metal Transformer Core and Coil Assembly. Amorphous alloy materials used in transformer cores are also disclosed in the group of U.S. Pat. Nos. 4,116,728; 4,262,233 and 4,528,481 issued to Joseph J. Becker, et al. and assigned to General Electric Company. While the use of amorphous metal material in transformer cores is well known, numerous problems have been encountered in such use and in the manufacture of such transformer cores.
Commercially available widths for amorphous metal strip are highly restricted. The vendors of amorphous metal strips want to cast the strip as wide as possible to minimize the cost of manufacturing the strip; however, there are practical limitations on the maximum width that can be cast. It has been suggested that in the foreseeable future the maximum width of strip will be about twelve inches. If a company wants a strip that is a "non standard size", the company will have to pay a premium price for that width. This imposes a restriction on the ability to design transformer cores from a variety of widths.
Amorphous metal strips are difficult to cut because they are hard and brittle. They are very abrasive and can damage mechanical cutting tools. Conventional mechanical cutting can produce irregular ends on laminations and can result in the material cracking and chipping. The cutting tool is rapidly dulled. Often chips are broken out of the cutting edge. Presently known alternative cutting methods for amorphous metal strips are slow and expensive.